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'Dielectrophoresis' in keywords
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1985 (1)
1980 (2)
1Author    Natalia Stoicheva, Iana Tsoneva, DimiterS. DimitrovRequires cookie*
 Title    Protoplast Dielectrophoresis in Axisymmetric Fields  
 Abstract    Pea protoplasts dielectrophoretic coefficients were measured in alternating electric fields of frequency 1 M Hz and voltage 5 V applied between two concentric cylindrical metal electrodes of outer and inner radii 0.24 mm and 1 mm, respectively. They do not vary significantly with solution osmolarity, but* show a clear expressed maximum in isotonic conditions; the values in 0.4 m , 0.5 m , 0.6 m and 0.7 m manitol solutions are (6.5, 10.2, 8.8 and 5.6) x lO * 24 A 2s4/kg, respectively. The average cell radii in those conditions are 14.2 (im, 14.6 [im, 13.8 jim and 13.6 [im. The radii of cell-to-electrode contacts follow the same dependence on the osmolarity as the dielectrophoretic coefficients; they do not depend on the applied voltages up to 18V. The times of cell approach near to the electrode were too short to be explained by the action only of the dielectrophoretic force; consequently an attractive force appeared at very close approach. These results may be of use in future studies of membrane adhesion and fusion. 
  Reference    Z. Naturforsch. 40c, 735 (1985); received February 4 1985 
  Published    1985 
  Keywords    Protoplasts, Dielectrophoresis, Axisymmetric Fields 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0735.pdf 
 Identifier    ZNC-1985-40c-0735 
 Volume    40 
2Author    Peter Scheurich, Ulrich Zimmermann, Maja Mischel, Ingolf LamprechtRequires cookie*
 Title    Membrane Fusion and Deformation of Red Blood Cells by Electric Fields  
 Abstract    Human red blood cells suspended in a slightly hypotonic solution o f low electric conductivity were exposed to an inhomogeneous and alternating electric field (sine wave, 30 V peak-to-peak value, electrode distance 120 |im, 0.5 to 2 MHz). Due to the dielectrophoretic effect the cells align parallel to the field lines under the formation o f pearl chains. At high voltages (10 V amplitude) membrane fusion is observed between the adhered red blood cells in the pearl chains, whereby the chains become attached to the electrodes. In contrast to the pearl chains observed at voltages o f up to 5 V amplitude the resulting fused and uniform aggregates which exhibit no recognisable individual cells under the light microscope, remain stable, even after the alternating electric field has been switched off or after haemolysis in response to osmotic shock. The fused aggregates are highly elastic. If the field strength o f the applied alternating electric field is further increased they are stretched in the direction o f the opposite electrode. Frequently, bridges are formed between the two electrodes. The uniform bridges remain stable for some time even in the absence o f an electric field. The possibility o f cell fusion and its initiation by electrical breakdown of the cell membranes are discussed. 
  Reference    Z. Naturforsch. 35c, 1081—1085 (1980); received August 21 1980 
  Published    1980 
  Keywords    Deformability, Dielectrophoresis, Electric Breakdown, Erythrocytes, Fusion 
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 TEI-XML for    default:Reihe_C/35/ZNC-1980-35c-1081.pdf 
 Identifier    ZNC-1980-35c-1081 
 Volume    35 
3Author    Maja Mischel, Ingolf LamRequires cookie*
 Title    Dielectrophoretic Rotation in Budding Yeast Cells  
 Abstract    Rotation of budding yeast cells in an alternating non-uniform electric field of low frequency was investigated. Rotation frequency was found to be proportional to field strength above a threshold, and varied from cell to cell. The threshold is inversely correlated with the mom ent of inertia of the cells, while the slope of rotation frequency versus field strength increases with the moment. Rotation frequencies varied between 1 and 10 cycles per second. Clear differences between the dielectrophoretic behaviour o f living and heat-inactivated yeast cells were observed. 
  Reference    Z. Naturforsch. 35c, 1111 (1980); received July 21/Septem ber 10 1980 
  Published    1980 
  Keywords    Dielectrophoresis, Rotation, Yeast, N onuniform Electric Fields 
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 TEI-XML for    default:Reihe_C/35/ZNC-1980-35c-1111_n.pdf 
 Identifier    ZNC-1980-35c-1111_n 
 Volume    35